6 replies to this topic

[Graysmith]

What psi figure should be obtained for a good 1995 CC GSR. 4g93 turbo?

[leadfoot]

anything over 140 is usually considered "good" but to really guage the health of you engine as all gauges are different you want to do it this way

 

first do whats called a dry compression test. measure each cylinder and note the pressure. you want as little difference between cylinders if a cylinder is more than 10 psi lower than other this generally indicates an issue with that cylinder.

 

now go and put about a teaspoon in each cylinder use a syringe or something so you can get down past the spark plug hole and get the oil on the cylinder wall our engine run a dish top piston so unless you want to go putting 13-15 cc's of oil in each cylinder you want to get it on the walls not the piston tops. run the test again you want to see a small (less than 5-10 psi) increase. a small increase will indicate slightly worn rings to good health a big increase is worn rings no rise will indicate bad valves.

 

my 4g93turbo read 150psi

[Dave_GSR1.8]

I've never seen a figure quoted by Mitsubishi but I may not be looking in the right places; there may not be a definitive number out there.

 

FYI my 4g93t (stock) gave 180 psi (dry) across all four cylinders. Not sure how accurate that number is, as it seems a bit higher compared to most other posters. I have seen numbers between 150 and 180 quoted on a number of different threads so as it seems to me that anything over 150 is OK. As khubner said, its more important that you get pretty much the same across all four cylinders. To be really thorough about it you should do a wet and dry compression test and a leak down test to pinpoint any probs.   

[leadfoot]

also every guage is different i think mine tops out around 150 as on of our 11:1 2tr-fe motor gave 150 aswell it's a bigger engine with higher compression and still reads 150 somethings fishy with the reading so if my gauge hits 150 we say all if good since a valve got stuck and read zero

[jack be nimble]

The dry reading for the 93t is in the fsm. Im not at laptop so I dunno what it says. But I seen it

[Graysmith]

On the dry test the readings were 135psi, very close all cylinders. I tried the oil test and came up to 180psi on all cylinders so it would seem the rings are shot even though the car runs quite well ( 1.15 at Wakefield Park) and does not burn much oil. 

[leadfoot]

that would only indicate possibly worn rings best to do now would be leak down test